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What Chemicals Do Pressure Washing Companies Use?

Pressure washing companies use a variety of chemicals for their services. In this article, we will cover the 3 most common chemicals used in pressure washing, what purpose they serve, and how to properly and safely use these chemicals for pressure washing a suburban home.

dirty siding pressure washing
House Covered in Algae in Wauwatosa, WI

Sodium Hypochlorite 

Sodium hypochlorite is a disinfectant widely used in pressure-washing solutions. It is effective at killing organic matter such as algae, mold, mildew, bacteria, and viruses. When applied to surfaces, sodium hypochlorite works by oxidizing and breaking down the cellular structures of organic contaminants, making them dead at a cellular level and much easier to remove with a pressure washer.

Sodium hypochlorite is particularly useful for removing stains and biological growth from surfaces like sidewalks, driveways, siding, and fences. It effectively tackles tough stains from algae, mold, and mildew.

To safely and effectively use sodium hypochlorite for pressure washing a home, follow these guidelines:

  • Rinse the plants in the surrounding area with water to prevent them from absorbing the sodium hypochlorite solution too readily, leading to them browning or dying.

  • Always dilute sodium hypochlorite according to the manufacturer's instructions. Typically, a solution containing 1 to 2% sodium hypochlorite is suitable for most pressure washing applications. Sodium hypochlorite is generally solid at a 5 to 15% concentration in the bottle and the pressure washer will dilute it further by mixing it with water.

  • Wear protective gear, including gloves, goggles, and long sleeves, when handling sodium hypochlorite to prevent skin and eye irritation. Fair warning, sodium hypochlorite will bleach clothes.

  • Apply the diluted sodium hypochlorite solution to the surface using a pressure washer with a 60° black nozzle. Allow the solution to sit for 5 to 10 minutes to effectively break down organic matter. If you notice the sodium hypochlorite beginning to dry (white, chalky appearance), begin pressure washing.

  • After the wait time, power wash the area thoroughly to remove any remaining sodium hypochlorite. 

pressure washing
After Sodium Hypochlorite in Wauwatosa, WI

Detergents & Degreasers

Detergents are specially formulated cleaning agents designed to break down dirt, grime, and other surface contaminants. They often contain surfactants and emulsifiers that help lift and suspend dirt particles on vinyl siding, wood decks, concrete, and patio furniture, allowing them to be easily rinsed away.

Follow these guidelines for safely and effectively using detergents in pressure washing:

  • Choose a detergent formulated for pressure washing and compatible with the surface to be cleaned. For example, Purple Power is a common chemical for concrete washing.

  • Apply the diluted detergent solution to the surface using a pressure washer with a low-pressure nozzle or a chemical injector (i.e. siphon tube). Allow the detergent to sit for a few minutes to loosen dirt and grime.

  • For heavily soiled areas, use a hard-bristled broom to agitate the detergent.

  • After letting it sit, thoroughly rinse the surface with water using a pressure washer to remove the detergent residue and loosened gunk.

surface cleaning
Detergent Use On Concrete in Sussex, WI

Common Rust Removers

Rust stains can be a common eyesore on surfaces such as metal fences, outdoor furniture, and concrete driveways. To effectively remove rust stains during pressure washing, various rust removers are available, each with its own active ingredients and application methods.

Rust removers are specifically formulated to dissolve and remove rust stains from surfaces without causing damage to the underlying material. They work by chemically converting iron oxide (rust) into a water-soluble compound that can be easily rinsed away.

Types of Rust Removers:

  • Oxalic Acid: Oxalic acid-based rust removers are one of the most common types available. They work by forming a soluble compound with iron oxide, effectively breaking down rust stains. Oxalic acid is particularly useful for removing rust from concrete, wood, and some metals.

  • Phosphoric Acid: Phosphoric acid-based rust removers are another effective option. They work by converting iron oxide into iron phosphate, which can be easily rinsed away. Phosphoric acid is often found in rust converters and can be used on metal surfaces such as fences, tools, and automotive parts.

  • Commercial Rust Remover Products: There are also numerous commercial rust remover products available on the market, often containing a combination of acids and other rust-inhibiting agents. These products are designed for specific applications and may offer added convenience and effectiveness. Our favorite is RustAid.

When using rust removers for pressure washing a suburban home, it's essential to follow these guidelines to ensure safe and effective results:

  • Surface Compatibility: Before applying a rust remover, check the compatibility with the surface material to avoid damage. Some rust removers may be corrosive to certain metals or coatings.

  • Test Patch: Perform a small test patch in an inconspicuous area to assess the effectiveness and any potential adverse reactions with the surface. If this is not done, any concrete sealer put on by a previous homeowner could be removed, leading to a patchy appearance.

  • Application: Apply the rust remover to the affected area using a pump sprayer ensuring complete coverage of the rust stains. Allow the rust remover to penetrate and work on the stains according to the manufacturer's instructions.

  • Agitation: For stubborn rust stains, gently agitate the surface with a hard-bristled broom.

  • Rinse: After the dwell time, thoroughly rinse the treated area using a pressure washer to remove the dissolved rust and leftover rust remover solution.

  • Protection: Wear gloves, long sleeves, goggles, and closed-toed shoes when applying rust remover to prevent damage to the skin and eyes.

EcoWash intern
EcoWash Representative with Customers

Pressure washing companies use a variety of chemicals in their services. Many of these can be attempted by homeowners but they can be risky for a novice. If you are a homeowner in the Midwest looking for a high-quality, trustworthy pressure washing company, reach out to EcoWash today.


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